Final answer:
The nurse should inform the client that memory loss is a known adverse effect of ECT, along with potential for elevated blood pressure during treatment.
Step-by-step explanation:
The nurse should inform the client that memory loss is an adverse effect of Electroconvulsive therapy (ECT). While ECT is used primarily for severe depression and can be very effective, it can also cause side effects such as transient memory loss, confusion, and physical side effects like headaches and muscle aches. Other effects, such as elevated blood pressure, may occur during or immediately after the treatment, but persistent memory loss is a more common concern associated with ECT treatments.